EP0166707A2 - Verfahren zur Messung des Feuchtigkeitsgehaltes in organischem Material und Apparat hierfür - Google Patents

Verfahren zur Messung des Feuchtigkeitsgehaltes in organischem Material und Apparat hierfür Download PDF

Info

Publication number
EP0166707A2
EP0166707A2 EP85850211A EP85850211A EP0166707A2 EP 0166707 A2 EP0166707 A2 EP 0166707A2 EP 85850211 A EP85850211 A EP 85850211A EP 85850211 A EP85850211 A EP 85850211A EP 0166707 A2 EP0166707 A2 EP 0166707A2
Authority
EP
European Patent Office
Prior art keywords
term
sub
moisture ratio
thickness
expression
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP85850211A
Other languages
English (en)
French (fr)
Other versions
EP0166707A3 (de
Inventor
Bengt Hane
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Stiftelsen Institutet for Mikrovagsteknik Vid Tekniska Hogskolan
Original Assignee
Stiftelsen Institutet for Mikrovagsteknik Vid Tekniska Hogskolan
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Stiftelsen Institutet for Mikrovagsteknik Vid Tekniska Hogskolan filed Critical Stiftelsen Institutet for Mikrovagsteknik Vid Tekniska Hogskolan
Publication of EP0166707A2 publication Critical patent/EP0166707A2/de
Publication of EP0166707A3 publication Critical patent/EP0166707A3/de
Withdrawn legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N22/00—Investigating or analysing materials by the use of microwaves or radio waves, i.e. electromagnetic waves with a wavelength of one millimetre or more
    • G01N22/04—Investigating moisture content

Definitions

  • the present invention relates to a method for measuring the moisture ratio of organic material, preferably wood, and apparatus herefor.
  • the invention is not limited to any particular field of application, however, but relates to the measurement of the moisture ratio of organic material.
  • One method of measuring the moisture ratio of organic material is to produce an electric or electromagnetic field therein.
  • the propagation or spread factor of the field is influenced chiefly by the water contained in the material.
  • the water content is normally determined by measuring resistance or capacitance. These values are a measurement of a complex material-constant in the water-bearing material.
  • the moisture ratio is defined as where W m is the weight of the material when wet, and W d is the weight of the material when dry.
  • the moisture ratio can be determined simply by measuring the water content.
  • the density of many organic materials, such as wood for example varies.
  • Damping or attenuation A is a measurement of the water content and the phase shift F1 is a measurement of the density and the water content.
  • Kraszewski maintains that the moisture ratio can be determined independently of both the density and the thickness of the material. This does not apply in general to the aforesaid formula 12, which describes the model in a general form, but solely when using the special model incorporated in Kraszewski's formula 13, namely and where V is the volume of the material and where k 1 - k 4 are constants.
  • the present invention relates to a method for measuring the moisture ratio of material, particularly of organic material, in which microwaves are transmitted to the material whose moisture ratio is to be determined; in which the transmitted microwaves are received subsequent to their transmission through said material; in which the damping (A) of the microwaves and their phase change (F1) upon transmission through the material is determined; and in which the so-called moisture ratio of the material is established with the aid of the determined damping (A) and phase-change values, the method being characterized by determining the term (W w /Y) from the expression where A is the measured damping and t is the thickness of the material, and where k 1 and k 3 are constants and are determined by a calibration process, and where the term W w /Y is the weight of water per unit area; and by determining the term (W d/ Y) from the expression where F1 is the measured phase change, in which expression the aforedetermined term +is used, where t is the thickness of the material, the term Wd/Y is the weight of
  • the invention also relates to apparatus of the kind set forth in Claim 4 and having the characteristic features disclosed therein.
  • the present invention is based on the understanding that the damping A is influenced by the thickness of the material, rather than the variable (W d/ Y), i.e. the weight of the material in a dry state per unit area, and that in the case of the majority of organic materials the phase change or shift (F1) varies as a function of the water content per unit area (W w/ Y) with the thickness.
  • unit area Y is meant the area perpendicular to the direction of propagation of the microwaves.
  • the terms (W /Y) and (W /Y) are abbreviated from the respective expressions and where V is the volume of the material and t the thickness thereof.
  • the thickness of the material is often known. Such is the case in saw mills for example, where a thickness measuring device is often on hand or can be readily installed.
  • the moisture ratio can be measured with a high degree of accuracy with the aid of the present invention, even in those cases where the density of the material varies.
  • the invention therefore affords a particular advantage when desiring to measure the moisture ratio of wood.
  • the density varies quite considerably between different wood species, such as between pine and spruce.
  • the damping A is determined by the relationship where t is the thickness and k 1 , k 2 and k 3 are constants.
  • phase change F1 is determined from the relationship where k 4 , k 5 , k 6 are constants.
  • Fig. 1 shows the principle relationship between damping per unit of thickness A/t and the weight of the water in the material per unit of volume
  • Fig. 1 illustrates the conditions prevailing at a microwave frequency of 16 GH z. At higher frequencies, up to 20 - 24 GHz, the dependency on the term W d/ Y is practically zero. The term W d/ Y cannot be ignored at lower frequencies, for example 2450 MHz, where the dependency is greater.
  • the damping or attenuation is affected more precisely by the water contained in the material and the phase change is affected to a still larger extent by the density at higher frequencies. This influence has a maximum at 20 - 24 GHz.
  • Fig. 2 illustrates the relationship between the damping A as a function of the water weight per unit area (W w /Y) in respect of a material having the thicknesses t 1 , t 2 , t 3 , i.e. the same relationship as that illustrated in Fig. 1 with the variables having been multiplied by t.
  • Fig. 2 shows three curves corresponding to the curve shown in Fig. 1. All curves have a common inclination beneath the respective knees of each curve.
  • the relationship (2) derives from the curve to the right of the knee.
  • This section of the curve describes the damping A as a function of the water weight per unit area W w/ Y.
  • the knee occurs at very low water concentrations.
  • the knee referenced (Ww/V)k in Fig. 1 corresponds to the knee (W w/ Y) k in Fig. 2.
  • the invention is also based on the understanding that in the case of the majority of organic materials the phase change or shift (F1) is influenced as a function of the water content per unit area (W w /Y) with the thickness, in a corresponding manner to that in which the damping (A) is affected. This influence has the same physical basis as that given above.
  • Fig. 3 illustrates the phase change per unit of thickness (F1/t) as a function of the water content per unit volume (W w/ V).
  • F1/t phase change per unit of thickness
  • W w/ V water content per unit volume
  • Fig. 4 illustrates the phase change (F1) as a function of the water content per surface unit (W /Y).
  • Fig. 4 also indicates that the phase change F1 depends upon the thickness of material of the kind with which the relationship of F1/t to W w/ V exhibits a knee, i.e. at least the majority of organic materials.
  • phase change F1 is measured and also inserted into the relationship or equation (3), whereafter the sole unknown term is obtained therefrom.
  • the term is determined by taking into account the thickness of the material and is thus far more accurate than would be the case if no attention had been paid to the thickness dependency, the value of the term taken from the relationship (3) affords a higher degree of accuracy.
  • the constants k 1 , k 31 k 4 , k 5 , k 6 are determined with the aid of a conventional calibration process.
  • the moisture ratio is obtained from the resultant values of the terms Ww and W d .
  • the relationship (2) determines the water content as a function of the thickness of the material and the term (W w/ Y) is inserted in the relationship (3), by means of which term (W d/ Y) is determined as a function of the thickness, a correct value of the moisture ratio is obtained even when the thickness and/or density of the material varies.
  • a curve characteristic according to Figs. 2 and 4 is formed from the common incline for organic material beneath the knee, the present invention can be applied with particular advantage for determining the moisture ratio of organic material where the thickness and/or density thereof varies from case to case or changes within a single piece of material.
  • a complicating factor when measuring the moisture ratio of organic material is that many organic materials swell, i.e. increase in volume, with increasing water content. Wood is a typical example of such material. In this case, it is preferred to compensate the dependency of the density on the water content.
  • compensation is made for the dependency of the material density on the water content of said material.
  • the density of the material is measured at the prevailing water content with the aid of the relationship where the term (W dd/ Y) is the term (W d/ Y) compensated for density variations due to the prevailing water content of the material.
  • the moisture ratio is then obtained in a manner analogous with the aforegoing, by utilizing the term i.e. the moisture ratio
  • the moisture ratio thus obtained provides an extremely accurate value of the water content of the material.
  • the present invention solves the aforementioned difficulties of measuring the moisture ratio of organic material with a high degree of accuracy, when the thickness and/or the density of the material varies and, in addition, when the density varies with the water content of the material.
  • Fig. 5 illustrates schematically an arrangement for measuring the moisture ratio of materials, incorporating apparatus according to the present invention.
  • the arrangement 1 located within the region defined by the chain line is of a known kind and will therefore only be described in brief.
  • the arrangement 1 includes a microwave oscillator 2 which generates a signal of frequency f .
  • This signal is passed to a so-called 3dB-hybrid 3, where the signal is divided between a reference channel 4 and a measuring channel 5.
  • a second oscillator 6 generates a signal of frequency f 1' which is substantially lower than the frequency f
  • the frequency f o exceeds 12 GHz and lies beneath 24 GHz, preferably 16 GHz.
  • the frequency f 1 is therefore suitably about 10 KHz.
  • the frequency f 0 is modulated in a modulator 7 with the frequency f 1 , so as to form the frequency f + f 1 .
  • the signal formed is transmitted by means of a first microwave antenna 8 and is received on a second microwave antenna 9.
  • the material whose moisture ratio is to be determined is introduced between the pair of antennae 8,9.
  • the signal received in the measuring channel 5 is mixed with the signal in the reference channel 4 in a mixer 11, such as to form a signal having the frequency f 1 , and is delivered through a conductor 12 to a signal processing circuit 13, to which a signal is also applied directly from the said second oscillator 6, through a conductor 14.
  • the phase change or shift F1 and the damping A are determined in a known manner in the signal processing circuit 13, by comparing the signals on lines 12 and 14 respectively.
  • a signal corresponding to the phase change F1 and a signal corresponding to the damping A is formed on the outputs 15,16 of the signal processing circuit.
  • the signals F1 and A respectively are passed through respective conductors 15 and 16 to a calculating unit which incorporates a microprocessor 17 or the like.
  • the microprocessor 17 incorporates a memory 18, which suitably comprises a RAM-memory or the like.
  • the keyboard 20 may be provided with a display 21 on which the thickness fed into the microprocessor is displayed.
  • the means 19 and the infeed unit 20 are connected to the memory 18 in which the pertinent thickness is stored.
  • the computer unit is adapted to calculate the value of the term (W w/ Y) in the expression where A is the damping obtained on the conductor 16 and t is the thickness of the material obtained from the memory 18, and where k 1 and k 3 are constants, which are also found stored in the memory 18.
  • the constants k 1 and k 3 are determined by a suitable conventional calibration process, whereafter the values obtained are introduced into the memory.
  • the computer unit introduces the value of the term (W w /Y) into the memory 18.
  • the computer unit 17 is also adapted to calculate the value of the term (W d/ Y) in the expression where F1 is the phase change or shift obtained from the conductor 15 and t is the thickness of the material.
  • the computer unit is adapted to collect the value of the term (W /Y) from the memory and insert said value into the expression for F1.
  • the constants k 4 , k 5 , k 6 are determined by a suitable conventional calibration process, whereafter the values obtained are introduced into the memory.
  • the constants, k 1 , k 3 , k 4 , k 5 and k 6 are determined prior to commencing the measuring process in question.
  • the computer unit 17 is adapted to then form the moisture ratio, by carrying out the calculation (W w /Y)/ (Wd/Y).
  • the computer unit is adapted, subsequent to determining the value of the terms (W w/ Y) and (W d/ Y) respectively to calculate the value of the term (W dd/ Y) from the expression while utilizing the value of the terms (W w /Y) and (W d /Y), where the term (W dd /Y) is the term (W d/ Y) compensated for density variations due to the prevailing water content of the material.
  • the constants k 7 and k 8 are also determined by means of a suitable conventional calibration process and introduced into the memory 18. This calibration process thus includes an empirical determination of the aforesaid expression in respect of a pertinent material.
  • the computer unit 17 is adapted to then form the moisture ratio, by making the calculation
  • the value of the moisture quotient (W w /Y)/(W d /Y) or, when applicable, (W w /Y)/(W dd /Y) is fed to a suitable visualizing device 22, such as a display unit, a writer, lamps or the like.

Landscapes

  • Physics & Mathematics (AREA)
  • Biochemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Electromagnetism (AREA)
  • General Health & Medical Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)
  • Length-Measuring Devices Using Wave Or Particle Radiation (AREA)
  • Investigating Or Analyzing Non-Biological Materials By The Use Of Chemical Means (AREA)
EP85850211A 1984-06-27 1985-06-18 Verfahren zur Messung des Feuchtigkeitsgehaltes in organischem Material und Apparat hierfür Withdrawn EP0166707A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE8403437 1984-06-27
SE8403437A SE449139B (sv) 1984-06-27 1984-06-27 Sett att meta fuktkvot i organiska material jemte anordning derfor

Publications (2)

Publication Number Publication Date
EP0166707A2 true EP0166707A2 (de) 1986-01-02
EP0166707A3 EP0166707A3 (de) 1988-08-17

Family

ID=20356367

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85850211A Withdrawn EP0166707A3 (de) 1984-06-27 1985-06-18 Verfahren zur Messung des Feuchtigkeitsgehaltes in organischem Material und Apparat hierfür

Country Status (6)

Country Link
US (1) US4675595A (de)
EP (1) EP0166707A3 (de)
JP (1) JPS6162845A (de)
FI (1) FI83267C (de)
NO (1) NO171431C (de)
SE (1) SE449139B (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2229275A (en) * 1989-02-24 1990-09-19 Koerber Ag Method of and apparatus for measuring the moisture content of commodities
FR2645962A1 (fr) * 1989-04-18 1990-10-19 Claude Marzat Dispositif de mesure d'humidite par micro-ondes de bouchons en liege ou autres produits dielectriques
EP0384593B1 (de) * 1989-02-23 1994-03-02 Texaco Development Corporation Mikrowellen-Überwachungsgerät von Wassergehalt

Families Citing this family (27)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4789820A (en) * 1986-01-08 1988-12-06 Hercules Incorporated Apparatus and method for sensing multiple parameters of sheet material
US5006785A (en) * 1986-04-23 1991-04-09 Chevron Research Company Microwave oil saturation scanner
US4791353A (en) * 1987-08-14 1988-12-13 Impact Systems, Inc. Scanning combination thickness and moisture gauge for moving sheet material
US4991915A (en) * 1988-08-04 1991-02-12 Imperial Chemical Industries PLC Manchester Polytechnic Microwave moisture sensing arrangement
GB8818512D0 (en) * 1988-08-04 1988-09-07 Ici Plc Microwave moisture sensing arrangement
US5315258A (en) * 1989-01-13 1994-05-24 Kajaani Elektroniikka Oy Method and apparatus for determining the moisture content of a material
ATE192576T1 (de) * 1989-08-15 2000-05-15 Commw Scient Ind Res Org Bestimmung des feuchtigkeitsgehalts durch mikrowellenphasenverschiebung und flächendichte
US5153595A (en) * 1990-03-26 1992-10-06 Geophysical Survey Systems, Inc. Range information from signal distortions
US5159343A (en) * 1990-03-26 1992-10-27 Geophysical Survey Systems, Inc. Range information from signal distortions
US5331284A (en) * 1992-04-21 1994-07-19 Baker Hughes Incorporated Meter and method for in situ measurement of the electromagnetic properties of various process materials using cutoff frequency characterization and analysis
US5455516A (en) * 1992-04-21 1995-10-03 Thermedics Inc. Meter and method for in situ measurement of the electromagnetic properties of various process materials using cutoff frequency characterization and analysis
US6107809A (en) * 1995-07-18 2000-08-22 Malcam Ltd. Device and method for determining the moisture content of tobacco
US5845529A (en) * 1995-07-18 1998-12-08 Malcam Ltd. Device and method for determining the moisture content of material
US6025724A (en) * 1997-11-20 2000-02-15 Malcam Ltd. Device and method for determining the moisture content of packaged material
US5621330A (en) * 1995-07-18 1997-04-15 Malcam Ltd. Device and method for determining the moisture content of a bale of material with multiple layers
US6111415A (en) * 1998-01-09 2000-08-29 Malcam Ltd. Device and method for determining the moisture content of a bulk material
NL1013057C2 (nl) * 1999-09-15 2001-03-16 Visser S Gravendeel Holding Inrichting en werkwijze voor het meten van de vochtigheidsgraad van teeltsubstraat zoals potgrond.
US7836910B2 (en) * 2004-12-29 2010-11-23 Rain Bird Corporation Soil moisture sensor and controller
US7236120B2 (en) * 2005-03-31 2007-06-26 United States Of America As Represented By The Secretary Of Commerce, The National Institute Of Standards And Technology Ultra-wideband detector systems for detecting moisture in building walls
DE102005040743B4 (de) * 2005-08-26 2007-12-27 Hochschule Magdeburg-Stendal (Fh) Verfahren und Anordnung zur zerstörungsfreien Prüfung
DE102008019940B4 (de) * 2007-04-21 2012-08-02 Esa Patentverwertungsagentur Sachsen-Anhalt Gmbh Anordnung zur mikrowellengestützten zerstörungsfreien Prüfung
JP5268151B2 (ja) * 2009-03-31 2013-08-21 日本電信電話株式会社 木材含水率同定装置および木材含水率同定方法
ES2385942B1 (es) * 2010-06-09 2013-06-13 Centro De Investigación Y Tecnología Agroalimentaria De Aragón (Cita) Dispositivo de medida del contenido en agua de elementos laminares.
DE102010041571B4 (de) * 2010-09-28 2012-11-22 Hauni Maschinenbau Ag Vorrichtung und Verfahren zur Verarbeitung und Messung von Eigenschaften eines bewegten Materialstrangs
US10520302B2 (en) * 2015-10-02 2019-12-31 Honeywell International Inc. Monitoring thickness uniformity
JP2019070535A (ja) * 2017-10-06 2019-05-09 マイクロメジャー株式会社 含水率等の測定装置及び測定方法
JP7366362B2 (ja) * 2019-10-18 2023-10-23 八光オートメーション株式会社 木材検査装置

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0082560A2 (de) * 1981-12-18 1983-06-29 Philips Patentverwaltung GmbH Anordnung zur Messung der Feuchte

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SU1116371A1 (ru) * 1983-05-17 1984-09-30 Киевский технологический институт легкой промышленности Способ измерени влажности материалов и веществ

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0082560A2 (de) * 1981-12-18 1983-06-29 Philips Patentverwaltung GmbH Anordnung zur Messung der Feuchte

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
CONFERENCE PROCEEDINGS OF THE 7th EUROPEAN MICROWAVE CONFERENCE, Copenhagen, 5th-8th September 1977, pages 267-272, Microwave Exhibitions and Publishers Ltd, Kent, GB; J. KALINSKI: "Self-adjustable microwave homodyne circuit for on-line simultaneous attenuation and phase measurements" *
IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS AND CONTROL INSTRUMENTATION, vol. IECI-23, no. 4, November 1976, pages 364-370, New York, US; A. KRASZEWSKI et al.: "An improved microwave method of moisture content measurement and control" *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0384593B1 (de) * 1989-02-23 1994-03-02 Texaco Development Corporation Mikrowellen-Überwachungsgerät von Wassergehalt
GB2229275A (en) * 1989-02-24 1990-09-19 Koerber Ag Method of and apparatus for measuring the moisture content of commodities
GB2229275B (en) * 1989-02-24 1994-02-02 Koerber Ag Method of and apparatus for measuring the moisture content of commodities
FR2645962A1 (fr) * 1989-04-18 1990-10-19 Claude Marzat Dispositif de mesure d'humidite par micro-ondes de bouchons en liege ou autres produits dielectriques

Also Published As

Publication number Publication date
FI852548A0 (fi) 1985-06-27
NO171431B (no) 1992-11-30
FI83267C (fi) 1991-06-10
SE449139B (sv) 1987-04-06
NO171431C (no) 1993-03-10
NO852551L (no) 1985-12-30
SE8403437L (sv) 1985-12-28
FI83267B (fi) 1991-02-28
JPS6162845A (ja) 1986-03-31
EP0166707A3 (de) 1988-08-17
SE8403437D0 (sv) 1984-06-27
US4675595A (en) 1987-06-23
FI852548L (fi) 1985-12-28

Similar Documents

Publication Publication Date Title
EP0166707A2 (de) Verfahren zur Messung des Feuchtigkeitsgehaltes in organischem Material und Apparat hierfür
US4788853A (en) Moisture meter
US4546311A (en) Arrangement for measuring moisture content
US5086279A (en) Method of and apparatus for measuring the moisture content of fibrous materials
NL8403905A (nl) Microgolf-vochtsensor.
WO2000009983A3 (en) Device and method for non-invasively measuring and determining moisture content and density of loose and packaged tobacco
SE7904696L (sv) Anordning for bestemning av snedfibrigheten i virke, serskilt i sagat virke
JPS6197556A (ja) 材料の含水率または乾燥成分含有率を測定する方法および装置
US20060220658A1 (en) Sensor system for moisture and salt measurement using microstripline
CA1130863A (en) Measurement of soil moisture
US6930492B2 (en) Using surface microwaves for measuring and determining density and/or moisture content of a material
US8188751B2 (en) Method and measuring instrument for measuring water content
JP3026223B2 (ja) 材料の水分含有量の測定方法および装置
US3879607A (en) Method of measuring the amount of substance associated with a base material
Kraszewski et al. Simple grain moisture content determination from microwave measurements
CA2424214C (en) Microwave moisture sensing via waveguide with slot array
EP0967479A3 (de) Verfahren und Vorrichtung zur Dichtemessung einer Substanz mit Kompensierung des freien Wassers
US6411106B1 (en) Method and apparatus for moisture sensing using microwave technologies
SE9804079L (sv) Förfarande och anordning för bestämning av hydridinnehåll
Antikainen et al. Comparison of the accuracy of two on-line industrial veneer moisture content and density measurement systems
GB2048492A (en) Improvements relating to the measurement of moisture content
JPS5531924A (en) Measuring unit for characteristics of substance
JPH0373832A (ja) 木材水分量測定器
DE3317200A1 (de) Verfahren und einrichtung zur messung der feuchte von schuettguetern
张金标 et al. MICROWAVE MEASUREMENT OF COMPLEX DIELECTRIC CONSTANT

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): AT BE CH DE FR GB IT LI LU NL

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

Kind code of ref document: A3

Designated state(s): AT BE CH DE FR GB IT LI LU NL

17P Request for examination filed

Effective date: 19880928

17Q First examination report despatched

Effective date: 19900208

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 19910226

RIN1 Information on inventor provided before grant (corrected)

Inventor name: HANE, BENGT